1. Field of the Invention
The disclosures herein generally relate to a coordinates input system, a coordinates input apparatus, and a coordinates input method.
2. Description of the Related Art
There are known in the related art coordinates input systems in which handwritten characters and the like are input by pointing devices such as an electronic pens into coordinates input apparatuses such as an electronic information boards having coordinates detection functions to display input results.
Such coordinates input systems propose various types of coordinate detection methods for detecting coordinates of the positions touched by a tip of the pointing device. For example, Japanese Laid-open Patent Publication No. 2011-145762 (hereinafter referred to as “Patent Document 1”) discloses an electrostatic capacitance type coordinates detection method.
The electrostatic capacitance type coordinates detection method has an advantage of simplifying a structure of the pointing device. Specifically, the pointing device may simply include a conductive member for connecting between the tip and a gripper of the pointing device without having to connect the pointing device to the coordinates input apparatus with wiring, or without having to perform communications between the pointing device and the coordinates input apparatus. This may lead to reduction in size and weight of the pointing device as well as reducing a failure frequency of the pointing device.
However, the electrostatic capacitance type coordinates detection method may also detect coordinates of positions touched by user's hands or fingers in addition to the coordinates of the positions touched by the pointing device. Hence, when the user tends to press the coordinates input apparatus with the user's fingers or hands while inputting handwritten characters and the like with the pointing device, the contact positions of the user's fingers or hands may be drawn on the coordinates input apparatus.
Hence, it is desired to implement a configuration of the coordinates input system employing the electrostatic capacitance type coordinates detection method capable of clearly identifying an input made by the pointing device and an input made by those other than the pointing device while maintaining the simplified structure of the pointing device.